Keratinization of stratified squamous epithelium may
occur at sites in the oral cavity where the mucosa is
subjected to habitual mechanical stress - such as continuous
trauma from chewing. This response is similar to the
formation of a callus on the hands of a manual laborer. Note
the typical appearance of the stratum corneum (A). No
nuclei are visible in contrast with the parakeratinized
variety. Re-identify the other structures labelled.